Design and Performance Improvement of GNSS Receivers Based on Robust Cascade Filter

Conventional Global Navigation Satellite System (GNSS) receivers are designed based on scalar tracking loops, which can lead to performance degradation or even loss of lock under high dynamic and weak signal environments. A cascaded vector tracking loops is designed to enhance the receiver performance in harsh environments. Firstly, the delay/phase locked loop is replaced by Kalman filter (KF), and fading factor is introduced into loop filter to improve the dynamic performance of loop tracking. Then, extended Kalman Filter (EKF) is adopted to fuse all channel information to estimate the receiver state, and the Chi-square detection is used to isolate channel fault information in vector feedback to enhance the robustness of vector tracking. Finally, the vehicle experiments results confirm the effectiveness and superiority of the proposed method in dynamic scenarios.